Here is the explanation of the Israeli soldiers' clown or chef hats from an article published during the Lebanon campaign of 2006.
Why are the Israeli soldiers wearing chef's hats?
By Daniel Engber
Explainer: Answers to your questions about the news.
Israeli Soldiers, Fashion Victims -- Why are they wearing chef's hats?
[Actually, they are clown hats....]
Prime Minister Ehud Olmert ordered Israeli troops to push deeper into Lebanon on Friday, as the U.N. Security Council continued to debate a possible cease-fire. Photos of Israeli soldiers taken throughout the war show them wearing big, floppy hats that look like shower caps. (Here's one example.) What's the deal?
They're for camouflage. The hat—called a mitznefet in Hebrew—attaches to a regular combat helmet and obscures its rigid, round shape. As the mitznefet flops about, it takes on an irregular form that's harder to recognize in a shadow or out of the corner of your eye. The hat also protects against the sun and the moon, which might reflect off the surface of the helmet. A standard mitznefet consists of reversible mesh fabric, with a greenish woodland camouflage print on one side and a brown desert print on the other. (You can buy one online from Tzahal for 25 bucks.)
Helmet covers are not a new idea. A U.S. Army field manual produced during World War II instructed a soldier to watch out for his helmet: "Its curved, familiar shape can be identified by the enemy. One of your first steps in preparing for the job of staying alive to fight is to disrupt both the form of your helmet and the strong, straight-lined shadow it casts." The manual goes on to suggest slipping a net or a rubber band over the headgear and then stuffing branches and leaves around the edges.
Modern American troops typically don't wear anything like the mitznefet, but they're still told to "cam up" their headgear with bits of foliage. Some soldiers attach strips from a cut-up battle dress uniform to their helmets, which turns a standard-issue K-pot into a camouflaged "rag top."
Bonus Explainer: What does the word mitznefet mean? One common translation is "clown hat," but the term has some more dignified connotations. The biblical Book of Exodus uses mitznefet to describe the ancient headgear of the Jewish high priests. As such, the word has been translated as "mitre" or "headdress." But some biblical scholars think mitznefet comes from the root "to wrap," and say that a better translation would be "turban." [repost from 8/14/06]